Citizen Crystal Seven Para Water Star – Automatic (Ref. 4-CSS2910-SA) (December 1966)

This elegant Citizen Crystal Seven dates from the mid-1960s and is an excellent example of Japanese watchmaking in the early automatic era. It combines precise engineering, classic design, and historical significance: With the "Crystal Seven," Citizen introduced a new generation of slim automatic movements, which were the first to feature seven synthetic jewels for the rotor suspension – hence the name "Crystal Seven."

Design & Character

The silver sunburst dial features applied indices and highly polished dauphine hands. A particularly striking feature is the rectangular day-date window below 12 o'clock, framed by a polished metal surround. Below the Citizen logo is the characteristic "7" emblem – the symbol of this model series – with the inscription "Crystal Seven" and the number 23 , which refers to the number of jewels in the movement.

The stainless steel case displays the typical case shape of the 1960s with clean lines, slightly domed acrylic glass and screw-down case back engraved with “Para Water Star” , Citizen’s early name for water-resistant cases.

The new black leather strap with white decorative stitching underlines the elegant appearance of this classic automatic vintage watch.

Technical data

• Model: Citizen Crystal Seven – Para Water Star
• Reference: 4-CSS2910-SA
• Serial number: 612xxxx
• Production date: December 1966 (based on serial number coding “612” → 1966 / December)
• Origin: Japan
• Movement: Citizen Automatic 5204 with 23 jewels
• Functions: Hour, minute, central second, day of the week, date
• Frequency: 18,000 A/h
• Power reserve: approx. 42 hours
• Case material: Stainless steel (SS)
• Diameter: 36.8 mm
• Height: 9.7 mm
• Lug-to-lug: 42.8 mm
• Lug width: 18 mm
• Weight (including strap): 44 g
• Glass: Acrylic glass (slightly curved)
• Base: screwed on, engraving “Crystal Seven – Para Water Star – Automatic”
• Crown: signed with Citizen logo
• Bracelet: New black leather strap with white stitching
• Clasp: Stainless steel pin buckle

Background & technical significance

The Crystal Seven was introduced in 1965 as the successor to the Citizen Jet series.
It was the first Citizen automatic watch with a day-date display and quickly became a successful model. The new movement used synthetic jewels not only in the gear train but also in the rotor bearing – hence the name "Seven" (for seven additional crystal jewels in the automatic mechanism).

The series marked Citizen's entry into the segment of high-quality, everyday automatic watches – with reliability, fine workmanship and, at the time, exceptional precision.

The inscription "Para Water Star" refers to Citizen's early water-resistant case designs. These models were equipped with seals that kept out splashes of water and dust – a technological advancement for their time.

Due to its age, the watch should no longer come into contact with water in order to protect the mechanism.

Condition

Very well-preserved vintage condition with only slight signs of wear.
Dial with slight patina, indices are clean, hands are original.
The mechanism runs precisely, and the date and day of the week change correctly.
The new leather strap is unworn.

Warranty (used)

This is a used item.
The limitation period for claims for defects (statutory warranty) is 12 months from delivery .

A notice:
As this is a vintage watch, water resistance cannot be guaranteed. To protect the movement, the watch should not come into contact with water or moisture .